1. Technical Field
The present disclosure relate to a system of verifying an operation of an electromagnetic flow meter, and more particularly to a system which can verify an operation state of the electromagnetic flow meter mounted in a pipe conduit in real time.
2. Related Art
The electromagnetic flow meter is formed in such a way that an exciting current is supplied to an exciting coil provided in the flow meter to generate a magnetic field in a pipe, and then, fluid is allowed to flow in the magnetic field so that an electromotive force proportional to a flow velocity generated in accordance with the Faraday's electromagnetic induction law is detected in an electrode to obtain a flow rate of the fluid in accordance with the electromotive force detected in the electrode. In a variety of fields including water and sewage works, food, a petroleum refining, chemicals, etc., are used various kinds of sizes from a micro-aperture to a large aperture that meet uses for measurement.
In such an electromagnetic flow meter, as forms of troubles in which the flow rate cannot be normally measured, a plurality of causes as described below are considered.
For instance, when an insulating material adheres to the electrode, an oscillation may sometimes appear in an output, or hunting or an overshooting of an instruction may occur, so that it is impossible to carry out a stable measurement of the flow rate.
Further, due to the trouble of an electric circuit, an excitation cannot be occasionally carried out, a calculating process cannot be carried out or a measured result is not displayed.
Further, when a mechanically attached position of the exciting coil shifts or floats from a predetermined position due to the cause that an attaching screw of the exiting coil forming a magnetic circuit is unfastened or falls as well as the adhesion of the insulating material to the electrode or the trouble of the electric circuit, a balancing property of a magnetic flux distribution is broken so that a measurement operation is abnormal.
Thus, for instance, the patent literature 1 proposes a system of monitoring an abnormal state such as fluid to be measured which has an electric conductivity exceeding a range of a specification or an adhesion of a foreign material to an electrode.
Further, when an abnormality arises in an exciting system of an exciting coil, for instance, the patent literature 2 proposes a unit of self-diagnosing that the abnormality is a trouble of either an over-excitation or an under-excitation of an exciting circuit.